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  1. #1
    Join Date
    Feb 2015
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    4

    Lightbulb Unanswered: Db2 auto backup retention

    Hi Team,

    As we have been following below db2 backup retention policy and we are taking everyday FULL ONLINE BACKUP of databases and archive logs as well....

    so can you please clarify if we have set the db cfg REC_HIS_RETENTN to 31 days & NUM_DB_BACKUPS to 4 then what will happen & will be in RECOVERY HISTORY FILE ??

    db2 update db cfg for sample using auto_del_rec_obj on;
    db2 update db cfg for sample using num_db_backups 4;
    db2 update db cfg for sample using rec_his_retentn 31;


    Thank you in advance for giving your valuable time & support to encourage Others...

  2. #2
    Join Date
    Apr 2006
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    Belgium
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    Provided Answers: 11
    why this setting
    db2 update db cfg for sample using num_db_backups 4 (and what if you take 4 backups in 1 day - for test/maintenance..)
    you can only keep 4 backup files - how to match with 31 days...
    Best Regards, Guy Przytula
    Database Software Consultant
    Good DBAs are not formed in a week or a month. They are created little by little, day by day. Protracted and patient effort is needed to develop good DBAs.
    Spoon feeding : To treat (another) in a way that discourages independent thought or action, as by overindulgence.
    DB2 UDB LUW Certified V7-V8-V9-V9.7-V10.1-V10.5 DB Admin - Advanced DBA -Dprop..
    Information Server Datastage Certified
    http://www.infocura.be

  3. #3
    Join Date
    Feb 2015
    Posts
    4
    Quote Originally Posted by przytula_guy View Post
    why this setting
    db2 update db cfg for sample using num_db_backups 4 (and what if you take 4 backups in 1 day - for test/maintenance..)
    you can only keep 4 backup files - how to match with 31 days...
    Well thank you Przytula,

    The same doubt is in my mind too.... I believe that if num_db_backups = 4 then rec_his_retentn also should have value 4 ( in case if we are taking 1 full backup per day in PRODUCTION for sure)

    I read, that after pruning history entry only the DBM can delete that entry related objects ( like backups / logs / load copies)

    but after seeing those settings like 31 days for rec_his_retentn & 4 for num_db_backups, I got a doubt that

    1, num_db_backups =4 > it will keep the 4 times of recently created backup objects
    2, rec_his_retentn = 31 > May be it will keeps only the history of the old objects upto 31 days old........ ( but not sure )

    for that only I raised the question that what the above settings will do ( please clarify )

    Please suggest any best settings if we are taking daily 1 backup in production environment and what those setting will do...... Thank you

  4. #4
    Join Date
    Apr 2006
    Location
    Belgium
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    Provided Answers: 11
    all details about all settings can be found at :
    http://www-01.ibm.com/support/knowle...5.html?lang=en
    Best Regards, Guy Przytula
    Database Software Consultant
    Good DBAs are not formed in a week or a month. They are created little by little, day by day. Protracted and patient effort is needed to develop good DBAs.
    Spoon feeding : To treat (another) in a way that discourages independent thought or action, as by overindulgence.
    DB2 UDB LUW Certified V7-V8-V9-V9.7-V10.1-V10.5 DB Admin - Advanced DBA -Dprop..
    Information Server Datastage Certified
    http://www.infocura.be

  5. #5
    Join Date
    Feb 2015
    Posts
    4
    Thanks a lot Przytula,

    Before posting this question, I've also been through that link twice.. but a little bit confused,

    But this time I've gone a little further by self explanation / exploration with that info then I got something that ( CORRECT ME if I'm wrong )

    mainly two settings are

    1 > auto_del_rec_obj ON
    2 > num_db_backups (a value)

    so based on those two setting only the recovery history pruning & recovery objects deletion will be taken place... no matter what the value specified in the REC_HIS_RETENTN ( other than < 0 )

    but the recommended value should be equal to the TIMESTAMP of last recovery object ( backup ), which is based on the value of num_db_backups



    Thanks for your valuable time :-)

  6. #6
    Join Date
    Apr 2006
    Location
    Belgium
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    2,514
    Provided Answers: 11
    REC_HIS_RETENTN : how many days to keep history about bu....
    auto_del_rec_obj on : when pruning history, related objects are also pruned/deleted
    num_db_backups : I always set it a very high value (100) and control prune/delete history and objects by script
    Best Regards, Guy Przytula
    Database Software Consultant
    Good DBAs are not formed in a week or a month. They are created little by little, day by day. Protracted and patient effort is needed to develop good DBAs.
    Spoon feeding : To treat (another) in a way that discourages independent thought or action, as by overindulgence.
    DB2 UDB LUW Certified V7-V8-V9-V9.7-V10.1-V10.5 DB Admin - Advanced DBA -Dprop..
    Information Server Datastage Certified
    http://www.infocura.be

  7. #7
    Join Date
    Feb 2015
    Posts
    4

    Thumbs up

    Got Cleared... Really Glad by your reply.

    Thank you Przytula. :-)

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